Reducing Flooding of Link State Information

1. A method for reducing flooding of link state information of a link state protocol in a network with multiple routers, comprising: pre-configuring a filtering strategy on a router interface for filtering link state information generated by a first router, wherein the filtering strategy is to enable link state database (LSDB) isolation between a second router associated with the router interface and the first router; and receiving or sending link state information generated by the first router according to the pre-configured filtering strategy via the router interface, wherein the filtering strategy is a global filtering strategy to enable LSDB isolation between the second router and first router, and the first router is not an upstream neighbour of the second router.

2. The method of claim 1 , wherein receiving or sending the link state information generated by the first router according to the global filtering strategy comprises: checking whether the first router is an upstream neighbour of the second router; if yes, receiving or sending the link state information via the router interface; but otherwise, discarding or not sending the link state information respectively.

3. The method of claim 1 , the method further comprises: sending, to the second router, default link state information to generate default routes to the first router.

4. The method of claim 1 , wherein the filtering strategy is an interface filtering strategy to enable LSDB isolation between the second router and first router based on a system ID of the first router.

5. The method of claim 4 , wherein receiving or sending the link state information generated by the first router according to the interface filtering strategy comprises: checking whether the system ID of the first router satisfies the interface filtering strategy; and if yes, receiving or sending the link state information via the router interface; but otherwise, discarding or not sending the link state information respectively.

6. The method of claim 1 , wherein the router interface is a router interface of the second router, or a router interface of an upstream neighbour of the second router.

7. The method of claim 1 , wherein the link state protocol is Intermediate System-to-Intermediate System (ISIS) and the link state information is a link state packet (LSP).

8. A network device for reducing flooding of link state information of a link state protocol in a network with multiple routers, wherein the network device is capable of acting as a router and comprises a processor to: pre-configure a filtering strategy on a router interface for filtering link state information generated by a first router, wherein the filtering strategy is to enable link state database (LSDB) isolation between a second router associated with the router interface and the first router; and receive or send link state information generated by the first router according to the pre-configured filtering strategy via the router interface, wherein the processor is to pre-configure a global filtering strategy to enable LSDB isolation between the second router and first router, and the first router is not an upstream neighbour of the second router.

9. The network device of claim 8 , wherein when receiving or sending the link state information generated by the first router according to the global filtering strategy, the processor is to: check whether the first router is an upstream neighbour of the second router; if yes, receive or send the link state information via the router interface; but otherwise, discard or not send the link state information respectively.

10. The network device of claim 8 , wherein the processor is further to: send, to the second router, default link state information to generate default routes to the first router.

11. The network device of claim 8 , wherein the processor is to pre-configure an interface filtering strategy to enable LSDB isolation between the second router and first router based on a system ID of the first router.

12. The network device of claim 11 , wherein when receiving or sending the link state information generated by the first router according to the interface filtering strategy, the processor is to: check whether the system ID of the first router satisfies the interface filtering strategy; and if yes, receive or send the link state information via the router interface; but otherwise, discard or not send the link state information respectively.

13. The network device of claim 8 , wherein the link state protocol is Intermediate System-to-Intermediate System (ISIS) and the link state information is a link state packet (LSP).